绿茶萃取物对N-亚硝基二乙胺体外合成的影响

Effects of green tea extracts on the synthesis of N-nitrosodiethylamine in vitro

中文关键词:  亚硝胺  N-亚硝基二乙胺  绿茶萃取物  茶多酚

英文关键词:nitrosamine  N-nitrosodiethylamine  green tea extracts  tea polyphenol

中文摘要:

      目的 研究绿茶萃取物对N-亚硝基二乙胺体外合成的影响。方法 采用分级萃取法获得绿茶二氯甲烷萃取物、乙酸乙酯萃取物、正丁醇萃取物和水提物, 利用高效液相色谱法研究各萃取物主要成分, 并在模拟胃液条件(37 ℃, pH 3)下萃取物与20 mmol/L 亚硝酸钠、40 mmol/L二乙胺进行反应, 分析其体外对N-亚硝基二乙胺(N-nitrosodiethylamine, NDEA)合成和NO2-清除的影响。结果 二氯甲烷萃取物主要成分为咖啡碱, 剩余水相中主要成分为多糖、蛋白质和氨基酸, 2种萃取物对NDEA的合成无显著影响; 乙酸乙酯萃取物和正丁醇萃取物主要成分为茶多酚, 能有效阻断NDEA的合成, 在4 mg/mL条件下阻断率分别为51.9%和45.7%, 其中EGCG含量与其阻断率呈显著正相关, 酸性降低和温度升高有利于其阻断作用; 乙酸乙酯萃取物在浓度低于1.6 mg/mL时可促进NDEA生成。结论 绿茶萃取物的主要有效成分为茶多酚, 能有效阻断NDEA合成, 在高浓度、强酸性环境和升温条件下阻断作用更强。

英文摘要:

      Objective To investigate the effects of green tea extracts on N-nitrosodiethylamine synthesis. Methods Green tea was extracted with different polarity solvents to obtain green tea dichloromethane extract, ethyl acetate extract, n-butanol extract and water extract. The constituents of the four extracts were analyzed by high performance liquid chromatography (HPLC), and the extracts were reacted with 20 mmol/L NaNO2 and 40 mmol/L diethylamine in simulated gastric solution (37 ℃, pH 3) to study the effects on synthesis of N-nitrosodiethylamine (NDEA) and scavenging of NO2- in vitro. Results The main component of dichloromethane extract was caffeine, main components of water extract were carbohydrates, proteins and amino acids, and the 2 extracts had no significant effect on the synthesis of NDEA. The main component of ethyl acetate extract and n-butanol extract was polyphenols, which could effectively block the synthesis of NDEA. The blocking rates were respectively 51.9% and 45.7% with the concentration of 4 mg/mL, and it was positively correlated with the concentration of EGCG. The decrease of acidity and the increase of temperature were beneficial to its blocking effect. Ethyl acetate extract could promote NDEA formation at the concentration less than 1.6 mg/mL. Conclusion The main component in green tea is tea polyphenols, which can effectively block the synthesis of NDEA. The blocking effect was stronger under the conditions of high concentration, strong acidity and high temperature.